Strowger Telecomms Glossary

  • ISDN Integrated Service Digital Network. A line which carries calls (voice and data) digitally rather than as analogue audiable signals. ISDN only became possible after the introduction of digital exchanges. More info on ISDN is Here.
  • POTS Plain Old Telephone System. Generally used to distingush analogue lines from digital ISDN lines or data networks.
  • PABX Private Automatic Branch Exchange. An exchange used for switching calls within an orgnaisation rather than between PSTN subscribers. Most PABX's do have connections to the PSTN for outside calls.
  • PMBX Private Manual Branch EXchange. The manual equiavlent of a PABX; a PMBX involves company employed operators manually switching each call using a manual switchboard. PBX is a general term for any private exchange.
  • PSTN Public Switched Telephone Network. This is the basic BT (et al) telephone network covering the country.
  • UAX Unit Automatic EXchange. A small rural exchange serving only a small community and thus not requiring engineers in attendance. There were various models of UAX, the most notable being the UAX12 and later UAX13. They were called 'Unit' because they were modular and could be scaled to the required capacity by adding 'units'.

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